sample has been tested. And to say it is a theory would involve a question of whether it is solid or dense.

Mr. DELAPLAINE. Do not understand me as making that statement. As soon as you can produce it for a dollar a ton, you will find all the railroads in the country using it, and furnishing all the money necessary to carry on the operation.

Mr. NEWTON. I have already prepared for the manufacturing of it on a large scale, and if it proves to be successful, as I think it will, I will produce fuel for the whole city of Fond du Lac next

year.

Paper by Hon. Hanmer Robbins was called for, upon "Transportation."

Mr. Robbins said,

MR. PRESIDENT: I did propose to discuss the question of transportation here sometime during the session, but I am not ready now. I would like to present my subject about the time the interest question comes up.

Adjourned until 2 o'clock, P. M.

AFTERNOON SESSION.

Mr. Benton asked if any gentleman had had experience with orchard grass, and if so he wished to know the results of their knowledge as to its milk-producing qualities, &c., also what kind of grass will yield the most and lengthen out the time of pasturage, and make pasturage more rich and productive.

Mr. Stilson said that in regard to mixing grasses, he thought it was an established fact that several varieties of grass will produce more than any one variety alone, but in regard to orchard grass he had no experience.

There seemed to be no gentleman present with experience on the subject, and the question was dropped.

PROTECTION FROM LIGHTNING.

BY PROFESSOR JOHN W. STERLING, OF THE UNIVERSITY OF WISCONSIN,

MADISON.

The object of this paper is not only to give practical directions as to the best means of protection against lightning; but also, and

mainly, to present in concise form, the scientific principles involved. The laws of electrical action must be clearly apprehended in order that one may be qualified to judge correctly in regard to the practical appliances proposed for warding off the effects of this destructive agent. It is in the light of such knowledge only, that the practical rules furnished by science can be successfully applied to the varying conditions constantly occurring.

We have undertaken this work, not because we have any thing new to present. The principles relating to the subject in hand have all been known to science since the time of Franklin. Nor have there been invented any improvements in the practical application of these principles, essentially different from what was suggested by Franklin himself.

It seems to us, however, that there is occasion for calling anew the attenton of farmers and others to this subject. Had we statistics at hand, we should be glad to lay before you definite information in regard to the loss of property and life caused by lightning. This, we think, would be found greater than is generally supposed. It is obvious that the means of protection, as actually applied, are far from effective. Buildings, apparently well provided with rods, are often struck by lightning-oftener, it may be, than those without them. A thorough understanding of the elementary principles of electricity would show the cause of this failure, and would restore confidence in the complete protection afforded by rods constructed and put up in accordance with the laws of electricity; and thus, we are assured, much property and many lives would be saved. It is the more important that these laws be generally understood, since so many false notions are disseminated by charlatans and so many impositions practiced by agents and venders of rods—each claiming for his wares superiority over all others. Moreover; what appears in the public prints on this subject, generally comes from interested parties, is partial, one-sided, and by no means trustworthy; while the publications of scientific men are, for the most part, in a form not readily accessible to common readers.

We desire here to call particular attention to an article on Atmospheric Electricity, by Professor Henry, secretary of the Smithsonian Institute, published under the head of Meteorology in the Patent Office Report for 1859. If the principles presented in this publication were generally understood and practically observed,

nothing further would be needed. We express our obligations to this paper in what follows.

The proper object of scientific investigation is the explanation of natural phenomena. This consists in a logical reference of these phenomena to some general law, or in pointing out the steps by which they may be deduced from some principle already established. Electricity is subject to laws as definite and uniform in their operation as any other department of nature. The general laws which govern electrical action are well established, and may be so stated as to be readily apprehended. A moderate degree of study and exercise of the reasoning powers would enable one to understand and apply these laws in explanation of most of the electrical phenomena which come under his notice. Besides the satisfaction derived from this exercise of the mental faculties, the knowledge thus obtained would be of great practical value. It would enable one to anticipate hurtful results and to devise proper means for warding off danger. A knowledge of the elementary principles of sciencenow happily within the reach of all-would afford the most effectual security against imposture, and form the best antidote for many of the evils which afflict society. We bespeak, then, your candid and earnest attention to a subject so intimately connected with the security of your crops and your homes.

We propose briefly to state the general laws or principles which govern electrical action-to point out some of the more important deductions from these principles, and finally to give some practical directions which should be observed in the construction and erection of conductors for the protection of property against injury from lightning.

For clearness of apprehension, we shall, in stating the laws of electrical action, use the language of Du Fay's theory, which assumes that the facts of ordinary electricity may be referred to the action of two subtle fluids, called by Du Fay vitrious and resinous, but now generally designated as positive and negative.

To explain electrical phenomena by the mechanical action of these fluids, the theory assumes the following postulates:

1. These fluids pervade all matter, its particles being so minute as to exist between the atoms of gross matter.

2. The particles of each of these fluids mutually repel each other with a force varying inversely as the square of the distance.

3. The particles of each one of these fluids attract those of the other with a force varying according to the same law.

4. Each of these fluids pass freely through some bodies and very imperfectly or not at all through others. The former are called conductors, the latter non- conductors.

5. When these two fluids exist in equal quantities in the same body, or when they are so united that their mutual attractions and repulsions are neutralized, there are no indications of electrical action, and the body is then said to be in its natural state.

6. By friction and other processes, these fluids may be separated and accumulated in different bodies. Then electrical action is exhibited.

7. When a body has an excess of one of the fluids it is said to be positively electrified, when it has an excess of the other it is said to be negatively electrified. This excess of either fluid is called free electricity. It is to this free electricity that all electrical phenomena are due.

In adopting this theory in regard to the nature of electricity, we would not be understood as asserting its absolute truth. Its value does not depend on this. If it furnishes, in exact and intelligable language, an expression of all the phenomena of electricity; if all the logical deductions from it are in strict accordance with observed facts, so that we are enabled by it to predict the form and time of their occurrance, it has the same value to us as though it were absolutely true in all that it assumes.

Having then a general law or theory by which, on mechanical principles we can anticipate and explain all phenomena of common or frictional electricity, we proceed to give some of the more important deductions, and especially those intimately connected with the subject under consideration. These deductions can all be verified by experiment.

Electrical phenomena belong to two general classes: 1, Statical Electricity: 2, Dynamical Electricity. The first relates to the phenomena of electricity at rest, the second to those of electricity in motion.

STATICAL ELECTRICITY.

Let us first turn our attention to some of the more simple phenomena. By friction or other processes, all bodies may become excited;

that is, may become charged with either the positive or negative fluid in excess of its natural share, If, for example, smooth glass be rubbed with woolen or silk cloth, the two fluids are separated; the positive fluid being accumulated on the glass, and the negative fluid in equal quantity on the cloth, as careful experiment proves. This excitement is shown by each body's attracting light substances, such as a pith-ball suspended by a silk thread. Now, if this pithball be touched by the excited glass, it will become electrified, that is, will receive free electricity from the excited body, and will be instantly repelled. The same takes place when sealing wax is rubbed with a woolen or silk cloth. That there are two kinds of electricity is obvious from the fact that two pith-balls, when both are electrified by contact with the excited glass or sealing wax, mutually repel each other; but if one be electrified by contact with the glass and the other with the wax, they mutually attract. all bodies are susceptible of being excited by friction with either positive or negative electricity.

So

To illustrate the difference between a conductor and non-conductor, let us suppose a globe mounted upon a glass standard. If the surface of the glass be free from moisture, and the air dry, this globe is said to be insulated, that is, surrounded by non-conductors. Suppose now, the globe to be touched by an excited body; if the globe be a good conductor, as metal, free electricity will instantly be diffused over its whole surface; if the globe be a non-conductor, as glass, it will become electrified only at, or a little beyond the point in actual contact with the excited body. So, if the electrified globe be touched with the finger, or connected with the ground by a good conductor, it will, if of metal, instantly part with all its free electricity; but if of glass, only that at or near the point in contact with the finger. Thus we may determine the character of different substances as conductors of electricity, by the time an electrified body is losing its free electricity when touched by rods formed of these different substances.

A body, insulated as above explained, will retain its free electricity for some time. If there be moisture on the surface of the glass standard, or in the air, it will soon conduct off the free electricity. If it be perfectly insulated, it will gradually lose its charge by connection, that is, the particles of air in contact with the body become electrified and then are repelled. These are followed by